title: Characterization of a recombinant mannobiose 2-epimerase from Spirochaeta thermophila that is suggested to be a cellobiose 2-epimerase.
abstract: A purified recombinant enzyme from Spirochaeta thermophila, that is suggested to be a cellobiose 2-epimerase, was a 47 kDa monomer with a specific activity of 29.2 U min(-1) for mannobiose. The epimerization activity of the recombinant enzyme for mannobiose was maximal at pH 7.0 and 60 °C with a half-life of 124 h. The enzyme exhibited a higher epimerization activity for mannose or the mannose moiety at the reducing end of β- and α-1,4-glycosyl-mannose than for glucose or the glucose moiety of β- and α-1,4-glycosyl-glucose. The enzyme was identified as a mannobiose 2-epimerase by evaluating its substrate specificity with not only glucose-containing sugars but also mannose-containing sugars. The activities of the reported cellobiose 2-epimerases from Caldicellulosiruptor saccharolyticus, Dictyoglomus turgidum and Ruminococcus marinus for mannobiose were higher than those for cellobiose, strongly suggesting that these enzymes are not cellobiose 2-epimerases but are mannobiose 2-epimerases.
authors.affiliation: Department of Food Science and Technology, Catholic University of Daegu, Gyeongbuk, Gyeongsan, 712-702, Republic of Korea.
authors.forename: Chang-Su
authors.initials: CS
authors.lastname: Park
authors.forename: Jung-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Seon-Hwa
authors.initials: SH
authors.lastname: Lee
authors.forename: Yeong-Su
authors.initials: YS
authors.lastname: Kim
authors.forename: Lin-Woo
authors.initials: LW
authors.lastname: Kang
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D002238:Carbohydrate Epimerases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002475:Cellobiose / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008351:Mannans / Q000378:metabolism*; D008970:Molecular Weight; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013142:Spirochaeta / Q000201:enzymology* / Q000235:genetics; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D008351:Mannans; D011994:Recombinant Proteins; C014647:mannobiose; D002475:Cellobiose; D002238:Carbohydrate Epimerases